Inserting and extracting control data using frequency components

Abstract

A method for inserting control data in a modulator comprising a plurality of frequency component inputs and a modulator output. The method is performed in the modulator and comprises receiving primary data subcarriers on respective frequency component inputs which are assigned for receiving primary data, receiving at least one control data subcarrier on a respective frequency component input which is not assigned to primary data, combining all frequency component inputs to one output signal, and providing the output signal on the output for transmission to a demodulator over a point-to-point medium.

The invention claimed is: 
     
       1. A method for inserting control data in a modulator comprising a plurality of frequency component inputs and a modulator output, the method being performed in the modulator and comprising:
 receiving primary data subcarriers on respective frequency component inputs which are assigned for receiving primary data; 
 receiving at least one control data subcarrier on a respective frequency component input which is not assigned to primary data; wherein receiving the at least one control data subcarrier comprises receiving the at least one control data subcarrier on a respective frequency component input for which power needs to be suppressed when transmitted over the air to avoid leakage to a neighbouring frequency band; 
 combining all frequency component inputs to one output signal; and 
 providing the output signal on the output for transmission to a demodulator over a point-to-point medium. 
 
     
     
       2. The method according to  claim 1 , wherein the step of combining comprises performing an inverse fast Fourier transform and a parallel to serial conversion. 
     
     
       3. The method according to  claim 1 , wherein the number of frequency component inputs is equal to two to the power of an integer. 
     
     
       4. The method according to  claim 1 , wherein the steps of receiving primary data subcarriers and receiving at least one control data subcarrier are performed in parallel. 
     
     
       5. The method according  claim 1 , further comprising the step of:
 receiving zero signals on frequency component inputs which are neither used for primary data nor for control data. 
 
     
     
       6. The method according to  claim 1 , wherein the primary data subcarriers form part of a transmission signal in accordance with Long Term Evolution, LTE. 
     
     
       7. A modulator for inserting control data, the modulator comprising:
 a plurality of frequency component inputs; 
 a modulator output; 
 a processor; and 
 a memory storing instructions that, when executed by the processor, cause the modulator to:
 receive primary data subcarriers on respective frequency component inputs which are assigned for receiving primary data; 
 receive at least one control data subcarrier on a respective frequency component input which is not assigned to primary data; wherein the instructions to receive at least one control data subcarrier comprise instructions that, when executed by the processor, cause the modulator to receive the at least one control data subcarrier on a respective frequency component input for which power needs to be suppressed when transmitted over the air to avoid leakage to a neighbouring frequency band; 
 combine all frequency component inputs to one output signal; and 
 provide the output signal on the output for transmission to a demodulator over a point-to-point medium. 
 
 
     
     
       8. The modulator according to  claim 7 , wherein the instructions to combine comprise instructions that, when executed by the processor, cause the modulator to perform an inverse fast Fourier transform and a parallel to serial conversion. 
     
     
       9. The modulator according to  claim 7 , wherein the number of frequency component inputs is equal to two to the power of an integer. 
     
     
       10. The modulator according to  claim 7 , wherein the instructions to receive primary data subcarriers and the instructions to receive at least one control data subcarrier are executed in parallel. 
     
     
       11. The modulator according to  claim 7 , further comprising instructions that, when executed by the processor, cause the modulator to:
 receive zero signals on frequency component inputs which are neither used for primary data nor for control data. 
 
     
     
       12. The modulator according to  claim 7 , wherein the primary data subcarriers form part of a transmission signal in accordance with Long Term Evolution, LTE. 
     
     
       13. A method for extracting control data in a demodulator comprising a plurality of frequency component outputs and a demodulator input, the method being performed in the demodulator and comprising: receiving one input signal on the input, the input signal having been transferred from a modulator over a point-to-point medium;
 separating frequency components of the input signal to the plurality of subcarriers for respective frequency component outputs; 
 providing primary data subcarriers on respective frequency component outputs which are assigned for providing primary data; and 
 providing at least one control data subcarrier on a respective frequency component output which is not assigned to primary data; wherein providing the at least one control data subcarrier comprises providing the at least one control data subcarrier on a respective frequency component input for which power needs to be suppressed when transmitted over the air to avoid leakage to a neighbouring frequency band. 
 
     
     
       14. The method according to  claim 13 , wherein the step of separating comprises performing a serial to parallel conversion and a fast Fourier transform. 
     
     
       15. The method according to  claim 13 , wherein the number of frequency component outputs is equal to two to the power of an integer. 
     
     
       16. The method according to  claim 13 , wherein the steps of providing primary data and providing control data are performed in parallel. 
     
     
       17. The method according to  claim 13 , further comprising the step of:
 combining the frequency components which are assigned for providing primary data and zero signals for frequency components which were used for control data subcarriers. 
 
     
     
       18. The method according to  claim 13 , wherein the primary data subcarriers form part of a transmission signal in accordance with Long Term Evolution (LTE).